Multiple sensor wearable and portable non-invasive respiration monitoring instrumentation

ABSTRACT

A system, apparatus, and method using multiple complementary sensors for the monitoring and wireless communication of several respiration characteristics—that is badge-size, wearable on the outside of clothing, and non-invasive.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed under 37 CFR 1.78 and 35 USC 119(e) to U.S.Provisional Application 62/632,907 (XT1802201), filed 20 Feb. 2018,which is incorporated by reference.

TECHNICAL FIELD

This disclosure relates generally to the non-invasive measurement ofbodily functions. More specifically, this disclosure relates to thesimultaneous use of multiple sensors and circuitry located within anon-intrusive wearable and portable instrument for the reliabledetection, characterization, and real time wireless communication of therespiration function. The instrument is safe, convenient to use andmaintain, and reliable, regardless of activity level and orientation ofthe wearer.

BACKGROUND

Apparatus to monitor the breathing of subjects has existed for manyyears. “Breathing is one of the most obvious signs of human vitality andactivity; however, it can also reflect the status of a patient and theprogression of an illness. The entire process, from inhalation to theexhalation, is referred to as the breathing or respiration cycle (RC).Respiratory rate indicates the frequency of breathing or the timebetween two consecutive RCs. Any alterations in the respiratory rate canhelp predict potentially serious clinical events, such as a cardiacarrest, or it may suggest that a patient be admitted to anintensive-care unit.” (Cretikos, M.A.; Bellomo, R.; Hillman, K.; Chen,J.; Finfer, S.; Flabouris, A. Respiratory rate: The neglected vitalsign. Med. J. Aust. 2008, 188, 657-659)

It is considered important to monitor the time pattern, volume, anddepth of respiration of a variety of subjects, such as infants,athletes, truck drivers, soldiers in the field, as well as those alreadyknown to suffer from dangerous medical conditions. It has also beendemonstrated that detailed knowledge of breathing characteristicssupports the ability to diagnose disease conditions. Such knowledge canbe used to recommend therapeutic procedures to prevent or forestallfurther permanent medical damage and/or death. Moreover, as respirationmonitoring products become more convenient and economical, it will beused routinely, including by those who are ill but are unaware of it.

Historically, respiratory measurements have not only lacked the costrequirements and convenience to encourage every-day and every-nightout-of-clinic use, but they have been unavailable to infants andchildren, who do not tolerate invasive or intrusive equipment. People ingeneral do not choose intrusive and/or inconvenient monitoring systemsfor themselves or loved ones, unless there is already a strongindication of adverse medical conditions.

Examples of intrusive and/or invasive respiration measurement systemsinclude belts with strain sensors, nasal air flow rate and/ortemperature sensing during the breathing cycle, and processedelectrocardiogram data. Examples of non-intrusive respirationmeasurement systems include photographic methods and ultra-widebandpulse radar. These latter systems are neither portable nor wearable.Clearly there is a need for a respiration measurement instrument systemthat is wearable, non-invasive, non-intrusive, and portable.

BRIEF SUMMARY

This Brief Summary is provided as a general introduction to theDisclosure provided by the Detailed Description and Figures, summarizingsome aspects of the disclosed invention. It is not a detailed overviewof the Disclosure and should not be interpreted as identifying keyelements of the invention, or otherwise characterizing the scope of theinvention disclosed in this Patent Document.

The portable, wearable, and non-intrusive/non-invasive respirationmonitoring system described in the instant disclosure is contained in abadge-sized, light, and safe enclosure that easily attaches to theoutside of inner clothing, i.e. makes no contact with the skin. Allsensors, measurement circuitry, power source and management, signalprocessing, data storage, and wireless communication circuitry arecontained within the enclosure.

The present example embodiment includes three sensors, havingcomplementary uses to detect and characterize breathing, depending uponthe position and activity of the wearer, as well as the relative motionof the wearer and clothing. The detected and processed signals are ofsufficient quality to monitor several critical aspects of respiration:breathing rate, depth, volume, and pattern. These sensors draw extremelylow power and are intrinsically safe. They induce no electric currentswithin the body and make use of naturally occurring physical effectswithin the skin. In addition to said principal function, these sensorscould be used to detect and communicate, whether or not said monitoringsystem is or is not attached to a subject.

One sensor is a three-axis accelerometer that operates successfullyduring periods when the clothing to which the monitoring systemenclosure is attached is very thin and tight against thewearer/subject's body. A second sensor measures the capacitance betweenits electrodes and the body. It is useful when the monitor is up toseveral centimeters from the body, such as when attached to the outsideof a diaper. The third sensor operates efficiently when the clothing isseparated from the skin within the range of 1 to 10 centimeters, such ason the outside of loose, hanging clothing. Its set of electrodesdevelops electric potential differences that are caused by naturallyoccurring potential differences on the skin, through the intermediary ofthe electric field created by the latter.

Other aspects, features and advantages of the invention will be apparentto those skilled in the art from the following Disclosure.

BRIEF DESCRIPTION OF DRAWINGS

For a more complete understanding of this disclosure and its features,reference is now made to the following description, taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates a basic wearable multiple sensor respiration Monitoron three subjects.

FIG. 2 shows a block diagram of the Respiration Monitor attached to aHuman Body.

FIG. 3A, 3B displays prior work that established, by application of ECGprobes, potential gradients on the skin surface.

FIG. 4 displays prior work showing that body surface potentialvariations can be used to derive rate and other features of respiration.

FIG. 5 shows measured respiration data from an accelerometer containedin a wearable monitor designed by the inventor.

FIG. 6 shows measured respiration data from a capacitance sensorcontained in a wearable monitor designed by the inventor.

FIG. 7 shows measured respiration data from an electric field sensorcontained in a wearable monitor designed by the inventor.

DETAILED DESCRIPTION

The various figures, discussed below, and the various embodiments usedto describe the principles of the present invention in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the invention. Those skilled in the artwill understand that the principles of the invention may be implementedin any type of suitably arranged device or system.

In general, this disclosure provides the description of a novel,multiple complementary sensor contained in a non-intrusive, non-invasiveportable and wearable system to monitor respiration and its detailedcharacteristics.

Depending on the implementation, this technique can provide significantbenefits in a range of fields, such as detection and monitoring ofunfavorable health conditions indicated by specific respiration rates,patterns, volume, and depth.

FIG. 1 illustrates a basic wearable multiple sensor respiration Monitoron three subjects 100. The subject on the left is wearing anundergarment 101, with a Monitor assembly 102 that contains amultiplicity of sensors used for breathing and other bodily functions.One said sensor, 103, is designed to register the existence of anelectric field having some component in the horizontal direction bycreating an electric potential difference between the illustratedelectrodes. Sensor 103 and the remaining sensors (not shown) areconnected to measurement and processing circuitry as well as wirelesscommunications circuitry. Monitor 102 is smaller, relative to the sizeof the subject, than the one shown in the figure. Not shown in thefigure are any over-garments that cover the undergarment 101 and Monitor102, allowing the latter to be comfortable and unobtrusive. MonitorAssembly 102 could be attached to clothing on many parts of the body,including, as examples, to the outside of a diaper or sleepwear, asshown for the remaining two subjects in the figure.

FIG. 2 shows a block diagram of the Respiration Monitor 200 attached toHuman Body 201. FIG. 2A illustrates functioning of said accelerometermeasurement block 210 and capacitance measurement block 220, and FIG. 2Billustrates functioning of said electric field sensor block 230. Notshown is that all three sensors and processing circuitry are containedwithin the Respiration Monitor 200 Enclosure, and that the WirelessCommunication module 213 services everything in the Monitor.

The 3-axis accelerometer sensor 211 detects breathing when theRespiration Monitor Enclosure is in close contact with the body surface,including on the outside of thin clothing. The raw data from theaccelerometer sensor 211 is refined by advanced processing block 212,which includes filtering and other processing, such as artificialintelligence circuitry.

If the Respiration Monitor is 200 separated from the body surface but bynot more than about 5 centimeters, the capacitance measurement block 220detects breathing. Capacitor #1 223 electrodes include the one shown inthe Figure and the body surface. Correspondingly, Capacitor #2 224electrodes include the one shown in the Figure and the body surface. Thecapacitance meter 221 sees the two capacitors 223, 224 as a seriescircuit. The relative positions of the body surface and Monitor 200modulate the capacitance seen by the meter 221. The advanced processingcircuitry 222 distinguishes the breathing curve from any miscellaneousmotion of loose clothing. This capacitive measurement block 220 operatesin both low and high humidity environments.

When the Subject is active and wearing loose clothing, separation of thebody surface and Respiration Monitor may exceed several centimeters. Inthis case, the Electric Field measurement block 230—depicted in FIG.2B—which operates with a separation of up to about 10 centimeters, isutilized. It has been shown that electrical potential gradients 231exist on the skin, which are correlated with aspects of the breathingcycle, such as depth. Potential gradients 231 on the skin surface causeelectric fields 232 that extend beyond the skin surface. If the there isa finite component of the electric field 232 vector in the directionalong the axis of the electrode assembly 233, 234, a potential (voltage)exists between these electrodes. Said voltage is detected with anextremely high impedance (electrometer) amplifier 235 that includes anautomatic gain control feature to handle a large range of signal levels.

FIG. 3A, 3B displays prior work that established by application of ECGprobes the existence, magnitudes, and spatial and time patterns of saidpotential gradients on the skin surface. The captions therein adequatelydescribe the measurement results and are not repeated in the instantSpecification text.

FIG. 4 displays prior work showing that body surface potentialvariations, measured by a pair of ECG-type electrodes, can be used toderive rate and other features of respiration. A 37-lead ECG system wasused to identify the most favorable proximal location pairs to probe.

FIGS. 5, 6, and 7 show measured respiration data from the accelerometermeasurement module 210, capacitance measurement module 220, and electricfield measurement module 230 respectively. Said data was acquired fromsaid measurement modules as part of the complete portable, wearable andnon-intrusive/non-invasive respiration monitoring system 200 asdescribed in the instant disclosure. The data is raw, prior to theextensive cleanup processing contained with said monitoring system. Thelinear vertical scales shown are arbitrary. Hidden in the data may bepulse rate and/or ECG information, which may be recoverable usingvarious additional processing methods.

The details provided in the instant specification describe particularimplementations of systems for portable, wearable andnon-intrusive/non-invasive respiration monitoring. Other embodimentscould be implemented in any other suitable manner.

It may be advantageous to set forth definitions of certain words andphrases used throughout this patent document. The term “couple” and itsderivatives refer to any direct or indirect communication between two ormore elements, whether or not those elements are in physical contactwith one another. The terms “transmit,” “receive,” and “communicate,” aswell as derivatives thereof, encompass both direct and indirectcommunication. The terms “include” and “comprise,” as well asderivatives thereof, mean inclusion without limitation. The term “or” isinclusive, meaning and/or. The phrases “associated with” and “associatedtherewith,” as well as derivatives thereof, may mean to include, beincluded within, interconnect with, contain, be contained within,connect to or with, couple to or with, be communicable with, cooperatewith, interleave, juxtapose, be proximate to, be bound to or with, have,have a property of, have a relationship to or with, or the like.

While this disclosure has described certain embodiments and generallyassociated methods, alterations and permutations of these embodimentsand methods will be apparent to those skilled in the art. Accordingly,the above description of example embodiments does not define orconstrain this disclosure. Other changes, substitutions, and alterationsare also possible without departing from the spirit and scope of thisdisclosure, as defined by the following claims.

What is claimed is:
 1. A method to monitor respiration using anunobtrusive badge-size apparatus that could be mounted over or betweenlayers of tight or loose clothing, that makes use of a multiplicity ofcomplementary sensors, such as: an accelerometer for when said apparatusis either in contact with the skin or on the outside of thin, tightclothing; a capacitance sensor for when said apparatus is in short rangeof the body surface; an electric field sensor for when said apparatus isgreater than about 3 centimeters from the body surface.
 2. The method ofclaim 1, but also used to monitor pulse rate and/or Electrocardiogramfeatures.
 3. The method of claim 1, but also includes the ability todetect and report whether or not the apparatus is located on awearer/subject.